1+1/2+1/6+1/12+1/20+1/30+1/42+1/52+1/72=?更正：1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72

1+1/2+1/6+1/12+1/20+1/30+1/42+1/52+1/72=?更正：1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
1+1/2+1/6+1/12+1/20+1/30+1/42+1/52+1/72=?
更正：1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72

1+1/2+1/6+1/12+1/20+1/30+1/42+1/52+1/72=?更正：1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
你的题目写错了吧 ?
1+1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
=1+1/2 + 1/2 -1/3 +1/3 -1/4 +1/4 -1/5 +1/5 -1/6 +1/6-1/7+1/7-1/8 +1/8-1/9
=1+1-1/9
= 17/9
如题,答案已经给出.嘻嘻